1. Field of the Invention
This invention relates to a nose piece for a tool which can be easily adjusted to the proper relationship with a member to be received into the nose piece to permit the tool to perform a predetermined desired function on the member.
2. Summary of the Prior Art
In many tools, it is desirable to have a nose piece which has a proper desired relationship with the member adapted to be received through the nose piece so that the tool can properly perform its designed function on the member. One area, for example, in which a nose piece performs this function is on a tool for forming a blind rivet type fastener.
A blind rivet fastener comprises a rivet having an open tubular body with a flanged head. A mandrel stem is inserted through the rivet body with a mandrel head resting against the open end of the rivet body. The rivet body can be inserted into the opening in a workpiece, and by placing the nose piece of a rivet forming tool against the rivet flange and by pulling on the mandrel stem, the rivet body opposite the flange will be deformed by the mandrel head to form a secondary head on the rivet on the blind side of the workpiece. At the completion of the forming of the rivet, the mandrel head can break off from the stem to remain on the blind side of the workpiece to lock the rivet in the workpiece opening. The tools for performing this function can be either manually or power operated. Tools of this type are illustrated in U.S. Pat. Nos. 3,324,700; 3,254,522; and 4,517,820.
The nose piece acts as an anvil on the flange of the rivet against which the pulling force on the mandrel stem reacts during the setting or forming of the rivet. To obtain the required proper axial force on the rivet body when the mandrel stem is pulled, it is necessary that the nose piece react or rest at the juncture of the mandrel stem and the rivet flange as the stem passes through the rivet flange. If the nose piece is spaced from the juncture of the flange and stem, distorted non-axial forces would act on the rivet body. This could result in the mandrel head being pulled entirely through the rivet body destroying the attachment of the rivet in the workpiece opening. Further, if the nose piece is not at the mandrel stem-rivet flange juncture, the mandrel stem could be pulled at an angle to the rivet body axis resulting in an asymmetrical forming of the secondary head leaving a poor connection.
Since the rivet bodies and mandrel stems come in different diameters for use in various size workpiece openings, it has been found desirable in the past to supply the tools with different size nose pieces which can be substituted to accommodate the various sizes of rivets. U.S. Pat. Nos. 3,324,700 and 3,334,509 illustrate rivet setting tools having various sizes of nose pieces. These tools, however, require interchanging the nose piece to accommodate the size of the rivet being used. It is, therefore, desirable to have a single adjustable nose piece which can be easily varied in opening size to accommodate various size blind rivets.